you cant connect data pins(pink&green here but usually white and green) in parallel. hubs needed to manage signals. they can share +5V and ground(dont short 5V to ground) but then, power management wont work... also you will need more power for devices on all ports, computers usually wont put out more than 1A that is barely enough to run one drive "stable" so take it as 1A for each port. I use 10 port hub. it comes with 5V2A adapter but I use 5V5A adapter now. otherwise i cant run two usb harddisks at once. more than that is too much for thin wires and small adapters.